1. Field of the Invention
This invention generally relates to a cartoning machine and particularly to a flap gluing apparatus for applying glue to and fixing flaps of a carton.
2. Description of the Prior Art
A container box, such as a carton, generally includes a rectangular main body comprised of four side walls and four flaps each formed at one end of a corresponding one of the four side walls. When closing such a container box in accordance with the prior art machine, while transporting the container box on a conveyor belt, glue is applied to the flaps by a glue applying unit and then the flaps are folded together by a flap folding unit disposed downstream of the glue applying unit with respect to the advancing direction of the conveyor belt. Such glue applying and flap folding units are spaced apart from each other in the advancing direction of the conveyor belt in a carton processing line. However, since there are also provided other units in the carton processing line upstream and downstream of the glue applying and flap folding units, it sometimes occurs that the conveyor belt is temporarily brought to a halt, for example, due to malfunctioning of other units. In such a case, those container boxes located between the glue applying and flap folding units have flaps to which glue has already been applied but which have not yet been folded or affixed together. When the conveyor belt is again set in operation, those container boxes move past the flap folding unit; however, since the glue applied to the flaps is most likely dried and hardened, the flaps cannot be affixed together even if the flaps are folded together by the flap folding unit. Thus, those container boxes must be removed from the conveyor at the downstream side.